The is a Phase II research study will evaluate the effects of aspirin and clopidogrel, two FDA approved blood thinners that prevent platelet clumping (blood cells sticking together) in the blood and therefore prevent the formation of blood clots in the arteries. Both drugs are prescribed to patients like you to help prevent cardiovascular disease (heart attacks or strokes). This study will establish which is the best dosage of clopidogrel on the first day of treatment and whether the combination of the two drugs is better than each drug alone.